earth fill up with unity in small grid to fill up the sections next to wals

like the titel says i would like to have a modul in the sice maybe 2x2 or 1x1 so you can fill up the spaces next to wals. at the moment you need to deconstruk the wall then fill up then construck the wall again then you see ther is stil some tiles missing so deconstrukt again fill up then construkt again. if the problem not in the first laier of your building so the deconstrukt will spil mazterial on the section below what means you need to deconstrukt the section below too to repair everithing its a very tideous work so if you could fill in the missing parts with unity you can go atound all the deconstrukt. to balance you could make the unity cost high if you think it wil get to easy other wise